Cooperation only for high rewards - a solvable task-based study on free-ranging dogs

The benefits of group living mostly surpass the disadvantages like sharing of resources and competition over food, space and mates, driving the evolution of social organization. Group living can be facilitated by social tolerance and cooperation among the group members. Social canids (e.g. wolves) display cooperative breeding, hunting, and prosocial activities in different contexts. Unlike cooperative pack-living wolves (Canis lupus lupus), their descendants, domesticated dogs (Canis lupus familiaris), show varying levels of associations from solitary to stable social groups. Free-ranging dogs are group-living but prefer to forage solitarily, hence providing an excellent opportunity for investigating social tolerance and coordinated task performance among the members in various situations. We tested 113 adult-only groups of free-ranging dogs in three different tasks to investigate group responses and performance in problem-solving situations in the presence of an unfamiliar human. Task 1 (unfamiliar, single food reward) and 2 (familiar, single food reward) examined group responses and cooperation from the perspective of familiarity, while Task 3 (familiar, multiple food rewards) enabled us to test whether increased food rewards promote social tolerance and food sharing among the group members. Regardless of significantly higher performance in Task 2 compared to Task 1, cooperation and food sharing were significantly lower in both. Task 3 revealed a strong positive correlation between food sharing and social tolerance, but not between success and social tolerance, suggesting a tendency for cooperation. We conclude that context-dependent cooperation and tolerance among group members facilitate group-living in free-ranging dogs.\n\nSignificance statementGroup living is a common phenomenon in the animal world where the members of a group show social tolerance and co-operative behaviours towards each other. This need for cooperative intents increases manifolds while groups face different problem-solving situations in their day to day lives. Here, we tested a large number of free-ranging dog groups to understand general cooperative intents such as social tolerance and food sharing in different problem-solving conditions. We found shreds of evidence of context-dependent cooperation and social tolerance among group members with minimal display of aggression. It is not adaptive for the dogs to fight or display aggression over resources. Alternatively, use of subtle cues such as display of dominance and subordination seem to be more plausible mechanisms for the development of efficient scavenging strategies and maintaining hierarchy.